What Does This Code Do

\n## One Job, Done Simply: Paste Code, Get an Explanation\n\nWhat Does This Code Do (whatdoesthiscodedo.com) does exactly one thing: you paste someone else's code, and the AI explains it in plain language. No IDE plugin, no \"AI coding assistant\" grand narrative—just an input box and zero-friction entry. This minimalist product positioning targets real developer pain points: code reviews, inheriting legacy projects, reading open-source code you didn't write.\n\n## Who's Behind It and Why\n\nThe author, flurly, launched the project on HN as \"Show HN: AI explanations for other people's code,\" garnering 186 points and 128 comments. Flurly's insight: most AI coding tools are built around \"helping you write code,\" but developers often get stuck \"not understanding someone else's code.\" HN commenter 6510 put it well: \"Someone who can deliver a better explanation might [help] many distributed down the learning curve.\" This is exactly the gap flurly is trying to fill—making \"reading code\" as easy as writing it with Copilot.\n\n## Hands-On: Sharp Enough, But Far From Deep\n\nIn practice, the tool delivers on its promise. For example, HN user jurimasa pasted the famous Quake fast inverse square root code (see g/565aad7), and the AI correctly identified operations like \"subtracting the integer value from a predetermined constant (0x5f3759df).\" But there are clear limits: zzo38computer noted, \"The explanation isn't very elaborate, e.g. it does not explain why it uses that specific constant number.\" recuter deliberately renamed all variables and functions to meaningless placeholders (g/9f22a12), and the AI still only gave a mechanical, surface-level description—no insight into the algorithm's purpose. rvz added that with more complex language features (especially Rust), \"it confidently generates code that doesn't compile,\" making overconfidence a real risk.\n\n## The Privacy Wake-Up Call: Community Pressure Forced Action\n\nFlurly initially overlooked privacy. HN commenter scastiel warned: \"putting here code source from your job is probably highly against the rules of your company, and you may get FIRED!\" Worse, pasted code was by default shown publicly on the \"explanations\" page—\"That sounds pretty dangerous.\" Flurly responded quickly in the thread, promising to add a classifier to detect sensitive info (API keys, passwords) and a checkbox for opting out of public display. This \"community-forced product safety\" loop is a classic indie dev reality.\n\n## Tech Stack and Honest Limitations\n\nThe product is likely a lightweight frontend (Next.js or static site) plus a backend calling OpenAI's API. When juliansimioni pasted the Quake snippet, the site hit rate limits; flurly replied, \"Should be back up... for now!\" and amelius joked, \"Perhaps you can ask GPT to fix it ;)\"—hinting at a fragile backend. The real value is saving junior devs or cross-language collaborators that painful first half-hour of staring at unfamiliar code. But if you expect senior-level insight into design rationale, performance traps, or historical context, you'll be disappointed. It's a quick triage tool, not a code mentor.\n"}}],"usage":{"prompt_tokens":1498,"completion_tokens":851,"total_tokens":2349}}